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| tools:netgen [2026/09/26 13:37] – [Staticizers/keepers] rajit | tools:netgen [2026/09/26 13:40] (current) – [Staticizers/keepers] rajit |
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| When using weak inverters, the netlist generator computes the drive strength of the gate, using an effective resistance calculation. Specifically, resistance is computed in units of length/width for each transistor in the gate, and the worst path from the power supply to the output is selected. Note that this is a simple path-based algorithm, and it will not identify logically equivalent paths that operate in parallel and adjust the effective resistance accordingly. If the effective resistance calculation is not correct, it can be overridden using attributes (see below). The ''prs2net'' output reports the effective resistance computed for the gates in comments in the SPICE file generated. | When using weak inverters, the netlist generator computes the drive strength of the gate, using an effective resistance calculation. Specifically, resistance is computed in units of length/width for each transistor in the gate, and the worst path from the power supply to the output is selected. Note that this is a simple path-based algorithm, and it will not identify logically equivalent paths that operate in parallel and adjust the effective resistance accordingly. If the effective resistance calculation is not correct, it can be overridden using attributes (see below). The ''prs2net'' output reports the effective resistance computed for the gates in comments in the SPICE file generated. |
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| The strength of the weak feedback is determined based on the effective resistance of the opposing network. The ''p_n_ratio'' parameter is used to adjust for the fact that p-fets are opposing n-fets and and vice versa. Additionally, the ''weak_to_strong_ratio'' is used to determine how much weaker the weak inverter must be. | The strength of the weak feedback is determined based on the effective resistance of the opposing network. The ''p_n_ratio'' parameter is used to adjust for the fact that p-fets are opposing n-fets and and vice versa. Additionally, the ''weak_to_strong_ratio'' is used to determine how much weaker the weak inverter must be. The feedback inverter is also sized using the standard staticizer sizes, and it is weakened by connecting it in series with a long channel device that is always turned on. |
| ===== Attributes ===== | ===== Attributes ===== |
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